The Pegões Aqueduct is c.7km in length and was completed in 1619. It was built to bring clean water for all purposes to the Convent, and also supplies the large fountain in the Royal Cloisters. (Interesting article with photographs here.)

The aqueduct, 7km in length, bringing water to the ConventAqueduct of Pegoes (Google Maps)

There were many beautiful tower staircases and this one led to an upper level.

The Convent of Christ from an upper levelTomar Town Square with a statue of Gualdim Pais, and the Castle in the background